Feedback Animator.keepAnimatorControllerStateOnDisable = true should be default

If you do a simple animation (call it animation_A), for example disable a child gameobject (call its gameobject_01), then switch to another animation, gameobject_01 will return to its default state before running animation_A.
But if you finish animation_A then disable root gameobject ( gameobject containing the animator - example dead animation of an enemy), when you change to another animation, gameobject_01 will keep its changed state caused by animation_A.

It took me a long time to find the answer in countless questions, and I wonder why this is not Unity's default?
Answer link:
https://answers.unity.com/questions/919995/parameters-and-states-of-animator-reset-on-objects.html